1. Field of the Invention
This invention relates to apparatus and methods for uniformly distributing freely-falling, discrete particles of lignocellulosic material over an area.
2. Prior Art Related to the Disclosure
The invention disclosed below finds particular application with electrostatic orientation systems for mat-forming of wood-based composite panel products, such as waferboard, oriented structural board, or composite plywood. For optimum alignment, the lignocellulosic materials, particularly non-fibrous lignocellulosic particles, should be uniformly distributed over the area of the electrostatic orientation zone. The particles enter the electrostatic orientation zone in a free-fall condition where the strong electric field within the zone influences each particle for a time sufficient to electrically polarize and orient the particles in the direction of the electrostatic field.
Fiber-distribution systems of various kinds for lignocellulosic materials are known. A typical system is disclosed in U.S. Pat. No. 3,999,650, which discloses a plurality of conveyors arranged in an overlapping fashion such that one part of a flow of fibrous material from a first conveyor falls on a distributing brush at the bottom of a chute and the other part of the flow of material falls on a second conveyor. The material on the second conveyor falls partly on a second distributing brush and on a third conveyor. The distributing brushes distribute the material over an area; however, the brushes create air turbulence causing local irregularities in the distribution of the material.
Squirrel-cage rolls have been used in distribution systems merely for breaking clots of material but have not been used for uniformly distributing material for passage through an electrostatic orientation field.